FreeWheel has added $16.8 million in strategic funding from several top investors. The online video monetization startup says its fourth round of funding is coming from Walt Disney’s Steamboat Ventures, as well as existing backers Turner Broadcasting System, Battery Ventures and Foundation Capital (It’s the first time that FreeWheel has publicly disclosed that Turner is an investor).

FreeWheel’s platform — which lets publishers control who is selling ads against their syndicated online video content — has been adopted by MLB.com, Warner Bros. (NYSE: TWX) and CBS (NYSE: CBS), among others. The company also said today it has landed ESPN’s ESPN.com and ESPN3.com, as well as Discovery Communications’ AnimalPlanet.com and TLC.com as clients.

The new round brings FreeWheel’s total funding to more than $28 million. The startup — which was launched by several former DoubleClick executives two years ago — had raised $12 million in a third round last April.